Jaguar X-Type Check Engine Light
On the V6 the light most often means an oxygen sensor or a split PCV hose — both cheap. I'd read the codes with a reader that knows Jaguar codes, ignore P1111, and check hoses and sensor wiring before buying parts. On the diesels the warning is the glow-plug light flashing instead.
How bad is it · Safe to drive
Steady light, car driving normally — get the codes read this week
Most causes here are sensors and hoses that cost little and do no harm for a few days. A hesitation under load, a dead throttle or the temperature gauge at full is different: book it in now.
Which one applies to yours depends on your symptoms, your model year and what has already been done to it.
Likely causes, most common first
Read the check cost before the odds: a free check that rules a cause out beats a likely guess that costs money.
A failed oxygen sensor
The pre-cat linear sensors drift out of range with age rather than dying outright, and a heater circuit can fail on its own. The car usually drives exactly as before.
P1646 names bank 1, P1647 bank 2; P0037, P0161 or P0164 point at a heater circuit. No change in how it drives.
Bank 1 is the right-hand bank seen from the gearbox end, bank 2 the left. Check the connectors on the firewall and the shared O2 sensor supply fuse first — a bad contact sets the same code.
Replace the sensor the code names, for example a Jaguar-boxed one for about 165 USD. The rear-bank sensor by the firewall needs a slotted lambda socket or a crow-foot, or the inlet manifold off.
A split PCV or breather hose
The hose from the PCV system to the intake, or the front cam cover breather to the manifold, splits and lets in unmetered air. The mixture runs lean and the engine computer switches cruise off.
P0171 and P0174, an amber warning with Cruise Not Available, a rough idle, an engine that stops pulling above a certain rpm.
Look along the PCV and breather hoses for a slit, and listen round the two intake tuning valve O-rings and the brake booster hose with the engine idling. A lean code can also be the inlet manifold gasket — rule it out before buying a sensor. The tuning valve O-rings are cheap enough to renew rather than test, and a live fuel-trim reading on a scanner shows whether the leak has gone.
Replace the split hose. The light can take 5 or 6 cold starts to go out by itself, so don't chase it once the leak is fixed. When it was the manifold gaskets rather than a hose, new gaskets cure the hesitation and rough idle as well as the light.
The fuel pump driver module
The module that drives the in-tank pump can fail while the pump itself is fine, and fuel pressure sags exactly when the engine needs the most fuel.
A sharp hesitation under load — for example as the gearbox shifts into 5th — and code 2635, low fuel pump pressure. Fine at high revs and motorway speed.
If the light returns under the same load after being cleared, the fuel side is real, not a glitch. Rule out the other fuel causes before spending on the pump.
Fit a replacement fuel pump driver module first; the pump comes next only if the hesitation stays.
The fuel level senders in the tank
The tank carries two level senders. When one loses its signal, the engine computer can't run its fuel-vapour checks and lights the lamp, while the engine itself runs exactly as before.
A steady light at low mileage with no change in how it drives, and nothing found at the sensors and hoses above.
Have the code read before anything is ordered: the senders are worth suspecting only when it points at the fuel level input. If the light comes back soon after the repair, have the wiring to the senders looked at too.
Replacing the senders the code points to; on some cars the whole sending unit is renewed.
A wheel speed sensor or cracked ABS ring
The slotted ABS ring shrunk onto the outer CV joint cracks and the wheel speed reading goes erratic. Cruise and ABS both lean on that signal, so an engine light with Cruise Not Available can start at a wheel.
C1145, C1155, C1165 or C1175 — one per corner — or Cruise Not Available with no ABS warning at all. Straight after a wheel bearing job is a strong hint. The engine light can also come on together with the ABS light from nothing worse than a dirty wheel sensor.
Look at the ABS ring on each outer CV joint for a crack, and the sensor plug and wire. After a bearing replacement, check it was fitted with the sensor side facing the sensor — backwards, the wheel reads as stationary.
Worth trying before a driveshaft: an outer CV joint kit with a new ring, for example about £90 in parts and £50-60 labour. A backwards bearing simply goes back in the right way round.
The throttle body
The throttle is drive-by-wire: the position sensor and servo motor are inside the throttle body, the sender is on the pedal. When either fails, the engine computer takes over the throttle.
A red circle with (!), sometimes the engine light too, the idle climbs and the throttle stops responding. A minute with the engine off clears it until next time.
Read the codes to tell the pedal sender from the throttle body. The sensor isn't sold separately, so the whole throttle body is the smallest part.
Worth trying a rebuilt or exchange throttle body, for example about 400 USD against about 1200 USD new; quote the casting number when ordering.
The order to check them in
The point of the order is money: each step either rules a cause out or makes the next one worth doing. Green is free, amber costs a little, red is the one to arrive at last.
Read the codes with a reader that knows Jaguar
The X-Type has no service light, so this light always means a stored fault. Some Jaguar-only codes don't show on a basic reader — use one that reads them, or have a Jaguar specialist read it. At key-on the light should go out after about five seconds; one that stays lit is a stored fault.
freeSet aside P1111 and P1000
P1111 means every self-test has completed since the codes were cleared — not a fault. P1000 means they haven't finished yet. Work only from the codes above them.
freeAfter recent work, check what was touched
After a wash, give it about three normal drive cycles. After a new stereo, check nothing was spliced into the airbag wiring. On a new car, look for a small plug left loose under the engine cover. A light that comes back only on the same steep hill points at a wire breaking under strain — including the lamp's own wire.
freeLook along the PCV and breather hoses
Lean codes, cruise dropping out or a rough idle all start here. A split hose costs a few pounds.
cheapCheck wiring and the fuse before an O2 sensor
If the code names a sensor, check its connector on the firewall and the sensor supply fuse first. Then replace only the sensor the code names.
cheapCruise Not Available too, check the ABS rings
Look at each outer CV joint for a cracked ring, and at the wheel sensor plugs. Any recent bearing job goes first. With no engine light and only Cruise Not Available, look at the brake light switch above the pedal first: it can drop out of its seat, and a gentle push and quarter turn reseats it.
cheapAfter the repair, let the light go out
Disconnecting the battery doesn't clear the code, but it does lose the windows' one-touch close — hold the switch about 2 seconds after the window shuts to reset it. Either clear the codes with a reader or allow 5 or 6 cold starts. Before an emissions test, clear them and complete the drive cycle.
freeWhat it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar X-Type V6 MisfireIf the code names a cylinder — P0301 to P0306 — or the engine shakes under throttle.
- Jaguar X-Type Diesel Limp Mode, Gearbox Fault MessageOn a 2.0 or 2.2 diesel with a flashing glow-plug light or a Gearbox Fault message.
- Jaguar X-Type Battery Light On While DrivingIf the battery light comes on alongside the engine light.
- Jaguar X-Type DSC System Fault, ABS LightIf the ABS light, DSC System Fault or Cruise Not Available came on first.
- X-Type (X400) fuse box diagramsFor the O2 sensor supply fuse; numbering changes with the year, so choose yours on the page.
- Jaguar X-Type Gearbox FaultIf the engine light comes with a Gearbox Fault message.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
Ratings, fuse numbers and torque figures vary by model year and market. Read the legend on your own car before pulling anything, and use the figures in the manual for your car, not the ones in a video.
Check your VIN: exactly which car you have and which bulletins apply to it.